Liquid-cooled-type cooling device

ABSTRACT

A liquid-cooled-type cooling device includes a casing having a cooling-liquid flow channel. Fins are provided on an inner surface of a top wall of the casing. Each fin has a wavy shape on a horizontal plane perpendicular to a fin height direction. In a left fin of two adjacent fins, lines of intersection between the horizontal plane and right side surfaces of two slant portions connecting two adjacent wave crest portions and a wave trough portion therebetween intersect each other at a first point located on a first straight line. In a right fin, lines of intersection between the horizontal plane and left side surfaces of two slant portions connecting two adjacent wave trough portions and a wave crest portion therebetween intersect each other at a second point located on a second straight line. The first straight line is located on the right fin side of the second straight line.

BACKGROUND OF THE INVENTION

The present invention relates to a liquid-cooled-type cooling device which is applied to a semiconductor power converter of a vehicle or the like and which is adapted to cool a heat-generating body such as a semiconductor device.

Japanese Patent Application Laid-Open (kokai) No. 2007-201181 discloses a conventional liquid-cooled-type cooling device of the above-mentioned type. The conventional liquid-cooled-type cooling device includes a casing which has a top wall, a bottom wall, and a peripheral wall and on which a cooling-liquid inlet and a cooling-liquid outlet are formed, wherein a cooling-liquid flow channel is provided within the casing at a position between the cooling-liquid inlet and the cooling-liquid outlet. A heat-generating body is attached to an outer surface of the top or bottom wall of the casing. On an inner surface of a portion of the wall facing the cooling-liquid flow channel, a plurality of fins are provided such that they project into the cooling-liquid flow channel, extend in a flow direction of cooling liquid within the cooling-liquid flow channel, and are spaced from one another in the width direction of the cooling-liquid flow channel. Each fin has a wavy shape as viewed on a cross section taken along a horizontal plane perpendicularly intersecting the height direction of the fin, and has wave crest portions and wave trough portions formed alternately. A first fin of two adjacent fins is configured such that second-fin-side surfaces of two slant portions connecting two adjacent wave trough portions and a wave crest portion positioned between the two wave trough portions intersect the above-mentioned horizontal plane, whereby two lines of intersection are formed between the second-fin-side surfaces and the horizontal plane and intersect each other at a first point. The second fin of the two adjacent fins is configured such that first-fin-side surfaces of two slant portions connecting two adjacent wave crest portions and a wave trough portion positioned between the two wave crest portions intersect the above-mentioned horizontal plane, whereby two lines of intersection are formed between the first-fin-side surfaces and the horizontal plane and intersect each other at a second point. The two adjacent fins are arranged such that the first point is located on the first fin side in relation to the second point.

In the liquid-cooled-type cooling device described in the publication, the fins provided in the cooling-liquid flow channel are formed into a way shape so as to increase the fin area, to thereby improve cooling performance.

Incidentally, in the liquid-cooled-type cooling device described in the publication, as shown in FIG. 10, of two fins 40A and 40B, the left fin 40A is configured such that right side surfaces 43 a of two slant portions 43 connecting two adjacent wave trough portions 42 and a wave crest portion 41 located between the two wave trough portions 42 intersect the above-mentioned horizontal line, whereby two lines of intersection are formed between the right side surfaces 43 a and the horizontal plane and intersect each other at a first point P1. This first point P1 is located on a first straight line L1 extending in a front-rear direction. The right fin 40B is configured such that left side surfaces 43 b of two slant portions 43 connecting two adjacent wave crest portions 41 and a wave trough portion 42 located between the two wave crest portions 41 intersect the above-mentioned horizontal line, whereby two lines of intersection are formed between the left side surfaces 43 b and the horizontal plane and intersect each other at a second point P2. This second point P2 is located on a second line L2 extending in the front-rear direction. The first straight line L1 is located on the left side of the second straight line L2 with a relatively large spacing therebetween, whereby the above-mentioned point P1 of the left fin 40A is located leftward of the above-mentioned point P2 of the right fin 40B. Therefore, cooling liquid tends to flow straight between the two fins 40A and 40B, and is unlikely to flow along the fins 40A and 40B. Accordingly, the areas of the fins 40A and 40B which effectively act for heat transmission do not increase effectively, which limits the effect of improving cooling performance.

SUMMARY OF THE INVENTION

An object of the present invention is to solve the above-mentioned problem and to provide a liquid-cooled-type cooling device which can improve cooling performance.

To achieve the above object, the present invention includes the following modes.

1) A liquid-cooled-type cooling device including a casing which has a top wall, a bottom wall, and a peripheral wall, which has a cooling-liquid inlet and a cooling-liquid outlet formed thereon, and in which a cooling-liquid flow channel is provided between the cooling-liquid inlet and the cooling-liquid outlet, wherein

a plurality of fins projecting into the cooling-liquid flow channel and extending in a flow direction of cooling liquid within the cooling-liquid flow channel are provided on an inner surface of a portion of a wall selected from the top wall and the bottom wall of the casing onto which a heat-generating body is attached such that the heat-generating body is in contact with an outer surface of the selected wall, the potion of the selected wall facing the cooling-liquid flow channel, and the plurality of fins being spaced from one another in a width direction of the cooling-liquid flow channel;

each of the fins has a wavy shape as viewed on a cross section taken along a horizontal plane perpendicular to a height direction of the fins, and has wave crest portions and wave trough portions alternately formed thereon; and

the fins are configured and arranged such that the cooling liquid flows between two adjacent fins while meandering.

2) A liquid-cooled-type cooling device according to par. 1), wherein a first fin of two adjacent fins is configured such that two lines of intersection formed between the horizontal plane and second-fin-side surfaces of two slant portions connecting two adjacent wave crest portions and a wave trough portion located therebetween intersect each other at a point located on a first straight line; a second fin of the two adjacent fins is configured such that two lines of intersection formed between the horizontal plane and first-fin-side surfaces of two slant portions connecting two adjacent wave trough portions and a wave crest portion located therebetween intersect each other at a point located on a second straight line; and the first straight line and the second straight line coincide with each other or the first straight line is located on a side toward the second fin in relation to the second straight line.

3) A liquid-cooled-type cooling device according to par. 2), wherein the wave crest portions and the wave trough portions of each fin are rounded; and, as viewed on the horizontal plane, the point at which the two lines of intersection between the horizontal plane and the second-fin-side surfaces of the two slant portions intersect each other is located at a position at which imaginary lines extending toward the second fin from the second-fin-side surfaces of the two slant portions intersect each other.

4) A liquid-cooled-type cooling device according to par. 2), wherein the wave crest portions and the wave trough portions of each fin are made flat; and, as viewed on the horizontal plane, the point at which the two lines of intersection between the horizontal plane and the second-fin-side surfaces of the two slant portions intersect each other is located at a position at which imaginary lines extending toward the second fin from the second-fin-side surfaces of the two slant portions intersect each other.

5) A liquid-cooled-type cooling device according to par. 2), wherein the first fin of two adjacent fins is configured such that the two lines of intersection formed between the horizontal plane and the second-fin-side surfaces of two slant portions connecting two adjacent wave trough portions and a wave crest portion located therebetween form an angle of 110 to 150 degrees therebetween; and the second fin of the two adjacent fins is configured such that the two lines of intersection formed between the horizontal plane and the first-fin-side surfaces of two slant portions connecting two adjacent wave crest portions and a wave trough portion located therebetween form an angle of 110 to 150 degrees therebetween.

6) A liquid-cooled-type cooling device according to par. 2), wherein two adjacent fins have a spacing of 0.5 mm or greater therebetween.

7) A liquid-cooled-type cooling device according to par. 2), wherein two adjacent fins are connected together at their upper end portions or lower end portions via a connection portion, and a plurality of the connection portions are provided at upper and lower end portions, alternately, of all the fins, whereby all the fins and the connection portions constitute a fin unit; and the connection portions on the upper side of the fin unit are joined to the top wall of the casing, and the connection portions on the lower side of the fin unit are joined to the bottom wall of the casing.

According to the liquid-cooled-type cooling device of par. 1), a plurality of fins projecting into the cooling-liquid flow channel and extending in a flow direction of cooling liquid within the cooling-liquid flow channel are provided on an inner surface of a portion of a wall selected from the top wall and the bottom wall of the casing onto which a heat-generating body is attached such that the heat-generating body is in contact with an outer surface of the selected wall, the potion of the selected wall facing the cooling-liquid flow channel, and the plurality of fins being spaced from one another in a width direction of the cooling-liquid flow channel; each of the fins has a wavy shape as viewed on a cross section taken along a horizontal plane perpendicular to a height direction of the fins, and has wave crest portions and wave trough portions alternately formed thereon; and the fins are configured and arranged such that the cooling liquid flows between two adjacent fins while meandering. Therefore, the cooling liquid becomes likely to flow along the wavy fins. Accordingly, the areas of the fins which effectively act for heat transmission increase effectively, whereby cooling performance can be improved.

According to the liquid-cooled-type cooling devices of pars. 2) to 7), a first fin of two adjacent fins is configured such that two lines of intersection formed between the horizontal plane and second-fin-side surfaces of two slant portions connecting two adjacent wave crest portions and a wave trough portion located therebetween intersect each other at a point located on a first straight line; a second fin of the two adjacent fins is configured such that two lines of intersection formed between the horizontal plane and first-fin-side surfaces of two slant portions connecting two adjacent wave trough portions and a wave crest portion located therebetween intersect each other at a point located on a second straight line; and the first straight line and the second straight line coincide with each other or the first straight line is located on a side toward the second fin in relation to the second straight line. Therefore, the cooling liquid flows between two adjacent fins while meandering. Accordingly, the cooling liquid becomes likely to flow along the wavy fins, and the areas of the fins which effectively act for heat transmission increase effectively, whereby cooling performance can be improved.

According to the liquid-cooled-type cooling device of par. 5), cooling performance can be improved maximally, while an increase in pressure loss produced when the cooling liquid flows between two adjacent fins is suppressed effectively.

According to the liquid-cooled-type cooling device of par. 6), catching of a foreign object between two adjacent fins can be prevented effectively.

According to the liquid-cooled-type cooling device of par. 7), the fins can be readily provided within the casing.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing a liquid-cooled-type cooling device according to the present invention;

FIG. 2 is a sectional view taken along line A-A of FIG. 1;

FIG. 3 is a sectional view taken along line B-B of FIG. 2;

FIG. 4 is a perspective view showing a portion of a fin unit of the liquid-cooled-type cooling device of FIG. 1;

FIG. 5 is an enlarged view of a main portion of FIG. 3;

FIG. 6 is a graph showing the relation between cooling performance and pressure loss, and angles α and β of adjacent first and second fins, wherein the angle α of the first fin is an angle between lines of intersection formed between a horizontal plane and the second-fin-side surfaces of two slant portions of the first fin connecting two adjacent wave trough portions and a wave crest portion located therebetween, and the angle β of the second fin is an angle between lines of intersection formed between the horizontal plane and the first-fin-side surfaces of two slant portions of the second fin connecting two adjacent wave crest portions and a wave trough portion located therebetween;

FIG. 7 is a graph showing the relation between heat resistance and flow speed of cooling liquid flowing through a cooling-liquid flow channel for an embodiment and a comparative product;

FIG. 8 is a view corresponding to FIG. 5 and showing a modification of the fin unit;

FIG. 9 is a view corresponding to FIG. 5 and showing another modification of the fin unit; and

FIG. 10 is a view corresponding to FIG. 5 and showing fins of a conventional liquid-cooled-type cooling device.

DESCRIPTION OF THE PREFERRED EMBODIMENT

An embodiment of the present invention will next be described with reference to the drawings. Notably, throughout the drawings, like portions and like members are indicated by like reference numerals, and repeated descriptions are omitted.

In the following description, the upper, lower, left-hand, and right-hand sides of FIG. 2 will be referred to as “upper,” “lower,” “left,” and “right,” respectively. Further, the lower and upper sides of FIG. 3 will be referred to as “front” and “rear,” respectively.

In the following description, the term “aluminum” encompasses aluminum alloys in addition to pure aluminum.

FIGS. 1 to 3 show the overall structure of a liquid-cooled-type cooling device according to the present invention; and FIGS. 4 and 5 show the structure of a main portion of the cooling device. Notably, FIGS. 1 to 3 show a state in which a heat-generating body composed of a semiconductor device is mounted on the liquid-cooled-type cooling device of the present invention.

In FIGS. 1 to 3, a liquid-cooled-type cooling device 1 has a casing 2 composed of a top wall 3, a bottom wall 4, and a peripheral wall 5. The peripheral wall 5 of the casing 2 includes a left side wall 6, which extends in the front-rear direction and stands vertically; a right side wall 7, which extends in the front-rear direction, stands vertically, and is positioned in opposition to the left side wall 6; a rear side wall 8, which extends in the left-right direction and stands vertically; and a front side wall 9, which extends in the left-right direction and stands vertically. In the peripheral wall 5 of the casing 2, a cooling-liquid inlet 11 is formed at a front end portion of the left side wall 6 in a leftward projecting condition, and a cooling-liquid outlet 12 is formed at a rear end portion of the right side wall 7 in a rightward projecting condition. The cooling-liquid inlet 11 opens leftward, whereas the cooling-liquid outlet 12 opens rightward. The casing 2 is formed of an upper structure member 13 of aluminum and a lower structure member 14 of aluminum. The upper structure member 13 includes the top wall 3 and an upper peripheral-wall-formation section 5A, which serves as an upper half of the peripheral wall 5. The lower structure member 14 includes the bottom wall 4 and a lower peripheral-wall-formation section 5B, which serves as a lower half of the peripheral wall 5. A lower end portion of the upper peripheral-wall-formation section 5A of the upper structure member 13 and an upper end portion of the lower peripheral-wall-formation section 5B of the lower structure member 14 have integrally formed outward flanges 13 a and 14 a, respectively. The outward flanges 13 a and 14 a of the upper and lower structure members 13 and 14 are brazed together.

A cooling-liquid flow channel 15 is provided within the casing 2 to be located between the left side wall 6 and the right side wall 7 and between the cooling-liquid inlet 11 and the cooling-liquid outlet 12. The cooling-liquid flow channel 15 extends in the front-rear direction, and cooling liquid flows through the cooling-liquid flow channel 15 from the front side to the rear side thereof.

A heat-generating body H is attached to the outer surface of the top wall 3 or the bottom wall 4 of the casing 2 (in the present embodiment, the top wall 3). A plurality of fins 16 are provided on the inner surface of a portion of the top wall 3 facing the cooling-liquid flow channel 15. The fins 16 project downward from the inner surface, and extend in the front-rear direction (in a flow direction of the cooling liquid within the cooling-liquid flow channel 15). The fins 16 are spaced from one another in the left-right direction (the width direction of the cooling-liquid flow channel 15). Two adjacent fins 16 are connected together via a connection portion 17 at their upper end portions or lower end portions. A plurality of the connection portions 17 are provided alternately at upper and lower end portions of all the fins 16. Thus, all the fins 16 and the connection portions 17 constitute a fin unit 18 (see FIG. 4). The connection portions 17 on the upper side of the fin unit 18 are welded to the inner surface of the top wall 3 of the casing 2, and the connection portions 17 on the lower side of the fin unit 18 are welded to the inner surface of the bottom wall 4 of the casing 2.

Each fin 16 of the fin unit 18 has a wavy shape as viewed on a cross section taken along a horizontal plane F perpendicular to the fin height direction of the fins 16 (vertical direction) (see FIG. 2), and includes leftward projecting wave crest portions 19 and rightward projecting wave trough portions 21 formed alternately. The fin unit 18 is manufactured from aluminum through press work, bending work, forging, or the like.

FIG. 5 shows two adjacent fins of the fin unit 18, wherein the left fin is indicated by 16A, and the right fin is indicated by 16B. As shown FIG. 5, one of the two adjacent fins 16A and 16B (in the present embodiment, the left fin 16A) is formed such that the right side surfaces 22 a, facing the other fin (in the present embodiment, the right fin 16B), of two slant portions 22 connecting two adjacent wave crest portions 19 and a wave trough portion 21 located between the wave crest portions 19 intersect the above-mentioned horizontal plane F, to thereby form two lines of intersection which intersect each other at a point P1. This point P1 is located on a first straight line L1 extending in the front-rear direction. Meanwhile, the other fin; i.e., the right fin 16B, is formed such that the left side surfaces 22 b, facing the left fin 16A, of two slant portions 22 connecting two adjacent wave trough portions 21 and a wave crest portion 19 located between the wave trough portions 21 intersect the above-mentioned horizontal plane F, to thereby form two lines of intersection which intersect each other at a point P2. This point P2 is located on a second straight line L2 extending in the front-rear direction. The first straight line L1 is located rightward of the second straight line L2. Therefore, as viewed on the above-mentioned horizontal plane F, the point P1 (P2) of the fin 16A (16B) is located on a side toward the adjacent opposite fin 16B (16A) in relation to a single straight line L2 (L1) extending in the front-rear direction (the flow direction of the cooling liquid). Accordingly, in the cooling-liquid flow channel 15, the cooling liquid flows, while meandering, through a flow channel section 15 a between the two adjacent fins 16. Notably, the first straight line L1 and the second straight line L2 may coincide with each other.

Furthermore, in the case of the left fin 16A, an angle α is formed between the two lines of intersection between the above-mentioned horizontal plane F and the right side surfaces 22 a of two slant portions 22 connecting two adjacent wave trough portions 21 and a wave crest portion 19 located therebetween; and in the case of the right fin 16B, an angle β is formed between the two lines of intersection between the above-mentioned horizontal plane F and the left side surfaces 22 b of two slant portions 22 connecting two adjacent wave crest portions 19 and a wave trough portion 21 located therebetween. Preferably, each of the angles α and β falls within a range of 110 to 150 degrees. In the case where the angles α and β are excessively small, an excessively large pressure loss is produced when the cooling liquid flows through between the two adjacent fins 16. In the case where the angles α and β are excessively large, the effect of improving cooling performance may become insufficient. For reference, FIG. 6 shows the relation between the angles α, β, and pressure loss and cooling performance.

Moreover, preferably, the spacing S between the two adjacent fins 16A and 16B is 0.5 mm or greater. If the spacing S is excessively small, foreign objects, which may be contained in the cooling liquid, may be caught between the two adjacent fins 16A and 16B. Notably, the upper limit of the spacing S is about 2 mm. If the spacing S is excessively large, cooling performance may drop.

A portion of the interior of the casing 2 located upstream (frontward) of the cooling-liquid flow channel 15 serves as an inlet header section 23 communicating with the cooling-liquid inlet 11. A portion of the interior of the casing 2 located downstream (rearward) of the cooling-liquid flow channel 15 serves as an outlet header section 24 communicating with the cooling-liquid outlet 12. The internal height of the entire casing 2 is uniform; i.e., the inlet header section 23, the outlet header section 24, and the cooling-liquid flow channel 15 have the same height. Furthermore, each of the inlet header section 23 and the outlet header section 24 has a constant width (in the front-rear direction) over the entire length thereof. The inlet header section 23 has a square inflow end portion 23 a, which is located on the side toward the left side wall 6 and communicates with the cooling-liquid inlet 11, and the outlet header section 24 has a square outflow end portion 24 a, which is located on the side toward the right side wall 7 and communicates with the cooling-liquid outlet 12. The width (the width in the front-rear direction) of the inflow end portion 23 a of the inlet header section 23 is equal to that of the outflow end portion 24 a of the outlet header section 24.

The heat-generating body H, which is a semiconductor device, is joined to the outer surface of the top wall 3 of the casing 2 via a plate-shaped electrically insulating member I.

In the liquid-cooled-type cooling device 1 having the above-described configuration, a cooling liquid having flowed from the cooling-liquid inlet 11 into the inlet header section 23 through the inflow end portion 23 a dividedly flows into the flow channel sections 15 a of the cooling-liquid flow channel 15, each located between two adjacent fins 16. The cooling liquid then flows rearward through each flow channel section 15 a.

The cooling liquid having flowed rearward along the flow channel sections 15 a of the cooling-liquid flow channel 15 enters the outlet header section 24, and flows rightward within the outlet header section 24. The cooling liquid then flows out of the cooling-liquid outlet 12 via the outflow end portion 24 a of the outlet header section 24 located on the side toward the right side wall 7.

Heat generated from the heat-generating body H is transmitted to the cooling liquid which flows through the flow channel sections 15 a of the cooling-liquid flow channel 15, via the insulating member I, the top wall 3 of the casing 2, and the fins 16 of the fin unit 18. The heat-generating body H is thus cooled.

For reference, the relation between heat resistance and flow speed of the cooling liquid flowing through the cooling-liquid flow channel 15 of the liquid-cooled-type cooling device 1 of the above-described embodiment is shown in FIG. 7 by a solid line. Further, the relation between heat resistance and flow speed of the cooling liquid flowing through the cooling-liquid flow channel 15 of a comparative product which includes fins as shown in FIG. 10 is shown in FIG. 7 by a broken line. The results shown in FIG. 7 reveal that the liquid-cooled-type cooling device 1 of the above-described embodiment has an improved cooling performance, as compared with the comparative product having the same structure as the liquid-cooled-type cooling device described in Japanese Patent Application Laid-Open No. 2007-201181.

Notably, the results shown in FIG. 7 were obtained through computer simulation calculation performed under the conditions that the heat load from the heat-generating body H was 50 to 200 W and cooling liquid formed of water and having a temperature of 20 to 30° C. was supplied to the cooling-liquid flow channel, while the flow speed of the cooling liquid was changed within a range not greater than 5 m/s.

FIGS. 8 and 9 show modifications of the fin unit. Notably, in FIGS. 8 and 9 as well, of two adjacent fins of the fin unit, the left fin is indicated by 16A, and the right fin is indicated by 16B.

In the case of a fin unit 30 shown in FIG. 8, each of the fins 16A and 16B has a wavy shape as viewed on a cross section taken along the horizontal plane F perpendicular to the fin height direction of the fins 16A and 16B (vertical direction), and each of the leftward projecting wave crest portions 31 and the rightward projecting wave trough portions 32 is rounded.

Therefore, as viewed on the above-mentioned horizontal plane F, the point P1 of the left fin 16A, i.e., the intersection between two lines of intersection between the above-mentioned horizontal plane F and the right side surfaces 22 a of two slant portions 22 connecting two adjacent wave crest portions 31 and a wave trough portion 32 located therebetween, is located at a position where imaginary lines extending rightward from the right side surfaces 22 a of the two slant portions 22 intersect each other. Further, as viewed on the above-mentioned horizontal plane F, the point P2 of the right fin 16B, i.e., the intersection between two lines of intersection between the above-mentioned horizontal plane F and the left side surfaces 22 b of two slant portions 22 connecting two adjacent wave trough portions 32 and a wave crest portion 31 located therebetween, is located at a position where imaginary lines extending leftward from the left side surfaces 22 b of the two slant portions 22 intersect each other. As in the case of the fins 16A and 16B shown in FIG. 5, the points P1 and P2 are located on first and second straight lines L1 and L2, respectively, which extend in the front-rear direction. Since the first straight line L1 is located rightward of the second straight line L2, as viewed on the above-mentioned horizontal plane F, the point P1 (P2) of the fin 16A (16B) is located on a side toward the adjacent opposite fin 16B (16A) in relation to a single straight line L2 (L1) extending in the front-rear direction (the flow direction of the cooling liquid). Notably, the first straight line L1 and the second straight line L2 may coincide with each other.

In the case of a fin unit 35 shown in FIG. 9, each of the fins 16A and 16B has a wavy shape as viewed on a cross section taken along the horizontal plane F perpendicular to the fin height direction of the fins 16A and 16B (vertical direction), and each of the leftward projecting wave crest portions 36 and the rightward projecting wave trough portions 37 is made flat.

Therefore, as viewed on the above-mentioned horizontal plane F, the point P1 of the left fin 16A, i.e., the intersection between two lines of intersection between the above-mentioned horizontal plane F and the right side surfaces 22 a of two slant portions 22 connecting two adjacent wave crest portions 36 and a wave trough portion 37 located therebetween, is located at a position where imaginary lines extending rightward from the right side surfaces 22 a of the two slant portions 22 intersect each other. Further, as viewed on the above-mentioned horizontal plane F, the point P2 of the right fin 16B, i.e., the intersection between two lines of intersection between the above-mentioned horizontal plane F and the left side surfaces 22 b of two slant portions 22 connecting two adjacent wave trough portions 37 and a wave crest portion 36 located therebetween, is located at a position where imaginary lines extending leftward from the left side surfaces 22 b of the two slant portions 22 intersect each other. As in the case of the fins 16A and 16B shown in FIG. 5, the points P1 and P2 are located on first and second straight lines L1 and L2, respectively, which extend in the front-rear direction. Since the first straight line L1 is located rightward of the second straight line L2, as viewed on the above-mentioned horizontal plane F, the point P1 (P2) of the fin 16A (16B) is located on a side toward the adjacent opposite fin 16B (16A) in relation to a single straight line L2 (L1) extending in the front-rear direction (the flow direction of the cooling liquid). Notably, the first straight line L1 and the second straight line L2 may coincide with each other.

In the fin units 30 and 35 shown in FIGS. 8 and 9, each of the angles α and β of the left and right fins 16A and 16B are preferably falls within a range of 110 to 150 degrees, and the spacing S between the two adjacent fins 16A and 16B is preferably 0.5 mm or greater, as in the case of the fin unit 18 shown in FIG. 5. Notably, as described before, the angle α is an angle of the left fin 16A formed between two lines of intersection between the above-mentioned horizontal plane F and the right side surfaces 22 a of two slant portions 22 connecting two adjacent wave trough portions 21 and a wave crest portions 19 located therebetween; and the angle β is an angle of the right fin 16B formed between two lines of intersection between the above-mentioned horizontal plane F and the left side surfaces 22 b of two slant portions 22 connecting two adjacent wave crest portions 19 and a wave trough portion 21 located therebetween.

In the above-described embodiments, of all the fins 16, two adjacent fins 16 are connected together via the connection portion 17. However, the structure of the fins is not limited thereto. The fins 16 may be individually fixed to or integrally formed on the inner surface of a portion (facing the cooling-liquid flow channel 15) of a selected wall (the top wall 3 or the bottom wall 4) of the casing 2 onto which a heat-generating body is mounted such that the heat-generating body is in contact with the outer surface of the selected wall.

In the above-described embodiments, a cooling-liquid inlet is formed in one end portion of the left side wall 6 of the peripheral wall 5 of the casing 2, and a cooling-liquid outlet is formed in the opposite end portion of the right side wall 7 of the peripheral wall 5 of the casing 2. However, the arrangement of the cooling-liquid inlet and the cooling-liquid outlet is not limited thereto. The cooling-liquid inlet may be formed in one end portion of a wall selected from the left side wall 6 and the right side wall 7, and the cooling-liquid outlet may be formed in the opposite end portion of the selected wall. Alternatively, the cooling-liquid inlet and the cooling-liquid outlet may be formed in the top wall or the bottom wall of the casing such that they are spaced from each other. 

1. A liquid-cooled-type cooling device comprising a casing which has a top wall, a bottom wall, and a peripheral wall, which has a cooling-liquid inlet and a cooling-liquid outlet formed thereon, and in which a cooling-liquid flow channel is provided between the cooling-liquid inlet and the cooling-liquid outlet, wherein a plurality of fins projecting into the cooling-liquid flow channel and extending in a flow direction of cooling liquid within the cooling-liquid flow channel are provided on an inner surface of a portion of a wall selected from the top wall and the bottom wall of the casing onto which a heat-generating body is attached such that the heat-generating body is in contact with an outer surface of the selected wall, the potion of the selected wall facing the cooling-liquid flow channel, and the plurality of fins being spaced from one another in a width direction of the cooling-liquid flow channel; each of the fins has a wavy shape as viewed on a cross section taken along a horizontal plane perpendicular to a height direction of the fins, and has wave crest portions and wave trough portions alternately formed thereon; and the fins are configured and arranged such that the cooling liquid flows between two adjacent fins while meandering.
 2. A liquid-cooled-type cooling device according to claim 1, wherein a first fin of two adjacent fins is configured such that two lines of intersection formed between the horizontal plane and second-fin-side surfaces of two slant portions connecting two adjacent wave crest portions and a wave trough portion located therebetween intersect each other at a point located on a first straight line; a second fin of the two adjacent fins is configured such that two lines of intersection formed between the horizontal plane and first-fin-side surfaces of two slant portions connecting two adjacent wave trough portions and a wave crest portion located therebetween intersect each other at a point located on a second straight line; and the first straight line and the second straight line coincide with each other or the first straight line is located on a side toward the second fin in relation to the second straight line.
 3. A liquid-cooled-type cooling device according to claim 2, wherein the wave crest portions and the wave trough portions of each fin are rounded; and, as viewed on the horizontal plane, the point at which the two lines of intersection between the horizontal plane and the second-fin-side surfaces of the two slant portions intersect each other is located at a position at which imaginary lines extending toward the second fin from the second-fin-side surfaces of the two slant portions intersect each other.
 4. A liquid-cooled-type cooling device according to claim 2, wherein the wave crest portions and the wave trough portions of each fin are made flat; and, as viewed on the horizontal plane, the point at which the two lines of intersection between the horizontal plane and the second-fin-side surfaces of the two slant portions intersect each other is located at a position at which imaginary lines extending toward the second fin from the second-fin-side surfaces of the two slant portions intersect each other.
 5. A liquid-cooled-type cooling device according to claim 2, wherein the first fin of two adjacent fins is configured such that the two lines of intersection formed between the horizontal plane and the second-fin-side surfaces of two slant portions connecting two adjacent wave trough portions and a wave crest portion located therebetween form an angle of 110 to 150 degrees therebetween; and the second fin of the two adjacent fins is configured such that the two lines of intersection formed between the horizontal plane and the first-fin-side surfaces of two slant portions connecting two adjacent wave crest portions and a wave trough portion located therebetween form an angle of 110 to 150 degrees therebetween.
 6. A liquid-cooled-type cooling device according to claim 2, wherein two adjacent fins have a spacing of 0.5 mm or greater therebetween.
 7. A liquid-cooled-type cooling device according to claim 1, wherein two adjacent fins are connected together at their upper end portions or lower end portions via a connection portion, and a plurality of the connection portions are provided alternately at upper and lower end portions of all the fins, whereby all the fins and the connection portions constitute a fin unit; and the connection portions on the upper side of the fin unit are joined to the top wall of the casing, and the connection portions on the lower side of the fin unit are joined to the bottom wall of the casing. 